Comparison of Characterization of Cold Brew and Hot Brew Coffee Prepared at Various Roasting Degrees

Table 4

Volatile compounds in coffee beverages prepared with cold and hot brewing at different roasting degrees (μg/L).

Compound

Odor description

Sumatra

Yunnan

Cold brew

Hot brew

Cold brew

Hot brew

Light roasting

Medium roasting

Dark roasting

Light roasting

Medium roasting

Dark roasting

Light roasting

Medium roasting

Dark roasting

Light roasting

Medium roasting

Dark roasting

Furans

2-Acetylfuran

Sweet, amaretto, cocoa

^a

^b

^c

^a

^c

^a

^ab

^b

^a

^b

^b

2,2-Methylenebisfuran

Roasted

^a

^a

^b

^a

^b

^c

^a

^a

^b

^a

^a

^b

Difurfuryl ether

Nutty, earthy

^a

^a

^b

^a

^b

^c

^a

^b

^c

^a

^b

^c

2-Propionylfuran

Fruity

^a

^b

^c

^a

^b

^b

^a

^b

^c

^c

^a

^b

2-Vinylfuran

Phenolic

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

Furfuryl methyl sulfide

Onion, garlic, sulphury

^a

^b

^c

n.d.

n.d.

n.d.

^a

^b

^c

n.d.

^a

^b

Methyl furfuryl thiol

Roasted

n.d.

n.d.

n.d.

n.d.

^a

^a

^a

^b

^b

^a

^b

^b

2-Furanemethanol

Caramel

^c

^b

^a

^c

^b

^a

^c

^b

^a

^c

^b

^a

Furan-2-yl-methyl acetate

Sweet, fruity, banana

^a

^b

^c

^a

^b

^c

^a

^b

^c

^a

^b

^c

5-Methylfurfural

Perfume, caramel

^a

^b

^a

^a

^b

^a

^b

^c

^a

^b

^c

^a

Total

^b

^a

^a

^c

^b

^a

^a

^a

^a

^b

^b

^a

Pyrazines

2-Ethylpyrazine

Peanuts, butter, nutty

^a

^a

^a

^a

^a

^a

^a

^b

^c

^a

^a

^b

2,5-Diethylpyrazine

Nutty

^a

^a

^a

^a

^ab

^b

^a

^a

^b

^a

^a

^a

2,6-Diethylpyrazine

Nutty

^a

^b

^c

^a

^a

^b

^a

^a

^b

^a

^ab

^b

2-Methylpyrazine

Nutty, cocoa, roasted

^a

^ab

^b

^a

^bc

^c

^a

^b

^c

^a

^ab

^b

2,5-Dimethylpyrazine

Cocoa, nutty, meaty

^bc

^a

^c

^ab

^c

^a

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

2-Ethyl-6-methylpyrazine

Roasted, potato

^a

^bc

^c

^a

^bc

^c

^a

^ab

^b

^a

^a

^a

2-Ethyl-5-methylpyrazine

Nutty, green, roasted

^ab

^bc

^c

^a

^bc

^c

^a

^ab

^b

^a

^a

^a

2-Ethyl-3-methylpyrazine

Nutty, corn, bread

^a

^a

^a

^a

^ab

^b

^a

^ab

^b

^a

^ab

^b

3,5-Diethyl-2-methyl pyrazine

Nutty, meaty

^a

^ab

^b

^a

^a

^a

^a

^a

^a

^a

^a

^a

Ligustrazine

Nutty

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

^a

^a

^a

^a

^a

^a

Total

^a

^b

^c

^b

^a

^c

^a

^a

^b

Phenols

Phenol

Plastics, caoutchouc

^a

^ab

^b

^a

^b

^bc

^a

^b

^c

^a

^b

^c

4-Ethylguaiacol

Spicy, smoky, bacon

^a

^b

^c

^a

^b

^c

^a

^b

^b

^a

^b

^c

p-Cresol

Phenolic

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

Total

^a

^b

^c

^a

^b

^c

^a

^b

^c

^a

^b

^c

Pyrroles

2-Acetylpyrrole

Nutty, walnut, bread

^b

^a

^c

^a

^b

^bc

^a

^ab

^b

^a

^b

^c

1-Methylpyrrole

Herbs, wood

^a

^ab

^c

^a

^a

^a

^a

^a

^b

^a

^a

^b

1-Methylpyrrole-2-carboxaldehyde

Roasted, nutty

^a

^b

^c

^a

^b

^bc

^a

^b

^c

^a

^b

^b

1-Furfurylpyrrole

Plastics, waxiness

^a

^a

^b

^a

^b

^c

^a

^b

^c

^a

^b

^c

Total

^a

^a

^b

^a

^b

^c

^a

^b

^c

^a

^b

^c

Pyridine

Sour, pourri

^a

^b

^c

^a

^b

^c

^a

^b

^c

^a

^b

^c

Alkones

2-Butanone

Fruity

^c

^b

^a

^b

^ab

^a

^b

^b

^a

^a

n.d.

n.d.

2,3-Pentanedione

Sweet, cream

^b

^a

^a

^b

^b

^a

^b

^b

^a

^b

^b

^b

3,4-Hexanedione

Butter, amaretto, nutty

^a

^b

^c

^a

^a

^b

^a

^a

^a

^a

^a

^b

2,3-Butanedione

Butter, sweet, cream

^a

^ab

^b

^a

^ab

^b

^a

^a

^a

^a

^a

^a

3-Hexanone

Sweet, fruity, grape

^a

^a

^b

^a

^a

^a

^a

^a

^b

^a

^a

^a

2,3-Hexanedione

Sweet, caramel, butter

^a

^ab

^b

^a

^a

^a

^a

^a

^a

^a

^a

^a

3-Ethyl-2-hydroxy-2-cyclopenten-1-one

Sweet, caramel, maple

n.d.

^a

^b

^a

^c

^b

n.d.

n.d.

^a

n.d.

^a

^b

2-Hydroxyacetophenone

Phenolic, tobacco, herbs

n.d.

^a

^b

^a

^b

^c

^a

^ab

^b

^a

^a

^b

Total

^a

^a

^b

^a

^b

^ab

^a

^a

^b

^a

^a

^b

Aldehyde

2-Methylbutyraldehyde

Cocoa, coffee, nutty

^a

^ab

^b

^a

^ab

^b

^a

^a

^a

^a

^a

^a

Benzaldehyde

Bitter almond odor, nutty

^a

^b

^c

^a

^b

^b

^a

^a

^b

^a

^ab

^b

Crotonaldehyde

Flowery

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

^a

^a

n.d.

^a

n.d.

n.d.

Hexanal

Green, fruity

^c

^b

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

2-Methyl-3-(2-furyl)propenal

Perfume, cinnamon, wood

^a

^a

^b

n.d.

n.d.

^a

^a

^ab

^b

^a

^b

^c

Total

^a

^b

^ab

^a

^b

^b

^b

^c

^a

^a

^b

^a

Alcohols

2-Heptanol

Lemon, green, flowery

^a

^ab

^b

^a

n.d.

n.d.

^a

^a

^a

n.d.

n.d.

n.d.

3-Octanol

Oranges

^a

^a

^a

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

(Z)-linalool oxide

Flowery, sweet

^b

^a

^a

^b

^a

^a

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

(E)-linalool oxide

Flowery

^a

^a

^a

^a

^a

^a

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

Linalool

Oranges, flowery, sweet

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

Geraniol

Sweet, flowery, fruity

^b

^a

^a

^a

n.d.

n.d.

^a

n.d.

n.d.

^a

n.d.

n.d.

Hydroxyacetone

Sweet, caramel

^a

^a

n.d.

^a

n.d.

n.d.

^a

^a

n.d.

^a

^a

n.d.

Total

^b

^ab

^a

^b

^a

^a

^a

^a

^a

^a

^a

^a

Other

2,4,5-Trimethyloxazole

Nutty, roasted

^a

^a

^b

^a

^a

^a

^a

^a

^a

^a

^a

^a

Methyl disulfide

Sulphury, vegetables, onion

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

Indole

Animal, faeces

n.d.

n.d.

n.d.

n.d.

n.d.

n.d.

^a

^a

^a

^a

^a

^a

Total

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

^a

Total compounds

Results are presented as the as μg/L; n.d.: not detected. The superscript letters (a, b, and c) represent statistically significant differences () between roasting degrees for the same brewing method, as determined by a one-way ANOVA. indicates significant differences () based on a one-way ANOVA analysis between cold and hot brewing methods for the same degree of roasting.